This study examines how the alignment of content with one's beliefs (congruency) and the quality of that content influence perceived truthfulness of social media posts, and whether metacognitive skills mitigate confirmation bias towards more congruent content. Results were replicated in two samples: a university student sample (N = 96) and a social-network sample (N = 121). Participants rated the truthfulness of simulated social media posts about socially salient domains - migration and women's traditional gender roles. Five posts per topic were designed - four to either align with the participant's stance (congruent) on the topic or contradict it (incongruent), two of those four contained either high-quality, accurate information or low-quality, misleading content, with an additional fifth post mimicking a high-quality, balanced view. We expected that, overall, high-quality content would be deemed more truthful than low-quality content, and that content congruency would bias truth ratings—especially for individuals with stronger attitudes on the topic.


In line with our hypothesis, congruent and balanced posts that were factually accurate and high-quality were rated as more truthful than low-quality content. However, individuals with stronger attitudes toward topics differed more in truthfulness ratings between congruent and incongruent information, reflecting a stronger confirmation bias - particularly for content about women's traditional gender roles. The patterns of effects were similar across the two samples.


When accounting for individual differences in metacognitive skills (measured via a novel metacognitive skills questionnaire for information-processing contexts), the influence of congruency on truth ratings was reduced. Participants scoring higher in metacognitive skills exhibited a smaller confirmation bias in evaluating the truthfulness of content.


These findings highlight that topic-specific attitudes alter how congruent versus incongruent arguments, and their quality, are perceived as truthful, while metacognitive skills can help mitigate this bias, leading to more objective and accurate judgments.